Adobe Flash (formerly Macromedia Flash) is a multimedia platform used to add animation, video, and interactivity to web pages. Flash is frequently used for advertisements and games. More recently, it has been positioned as a tool for "Rich Internet Applications" ("RIAs").

Flash manipulates vector and raster graphics to provide animation of text, drawings, and still images. It supports bidirectional streaming of audio and video, and it can capture user input via mouse, keyboard, microphone, and camera. Flash contains an Object-oriented language called ActionScript.

Flash content may be displayed on various computer systems and devices, using Adobe Flash Player, which is available free of charge for common web browsers, some mobile phones and a few other electronic devices (using Flash Lite).

Flash files are in the SWF format, traditionally called "ShockWave Flash" movies, "Flash movies," or "Flash games", usually have a .swf file extension, and may be used in the form of a web page plug-in, strictly "played" in a standalone Flash Player, or incorporated into a self-executing Projector movie (with the .exe extension in Microsoft Windows). Flash Video files have a .flv file extension and are either used from within .swf files or played through a flv-aware player, such as VLC, or QuickTime and Windows Media Player with external codecs added.

Flash Player is a browser plugin, and cannot run within a usual e-mail client, such as Outlook. Instead, a link must open a browser window.

The Adobe Flash Professional multimedia authoring program is used to create content for the Adobe Engagement Platform, such as web applications, games and movies, and content for mobile phones and other embedded devices.

One of the uses of Adobe Flash is to create a flash intro, a piece of animated content displayed at the beginning of a website. Often, the main content is loading in the background, while the animated content is displayed in the foreground. The intent is to captivate the user's attention so that he or she does not stray from the site, although it may do the opposite as it slows the user from accessing the actual site and can be tedious for users with slow internet connections. The quality of such content is usually marketing-centric. Often a "skip" or "skip intro" button is prepared to allow more immediate access to the site's homepage.